Review on Zone Tech 12V Single Trumpet Air Horn - High-Quality Silver Single Trumpet Air Horn with Relay, Chrome & Compressor - Super Loud 150db for Trucks, Trains, Lorries, Boats, and SUVs by John Pound

Wanted to complement my new Hella horns with an air horn on my weekend truck (14 Tundra) and daily commuter car (03 Civic). Installed on Tundra so far with no problems, good sound, not noisy train, more like a noisy dump truck (so POSSIBLY legal). I put a toggle switch in with the horn so I can use my regular horns with our horns without the air horn (ok if I get stopped for annual checks too). The description says they come with a relay, I bought 2, no relay. Also, one of them had a damaged o-ring, which I replaced with PTFE tape (like the thicker Teflon tape commonly used for gas fittings). So far no problems. I noticed a very slight delay between my regular horns firing and these ones firing (e.g. ¼ - ½ second). I'll probably update my truck settings if/when they die.